For 70 years, doctors handed out aspirin with no idea how it worked. Billions of pills, zero explanation. When John Vane finally cracked the mechanism in 1971, they gave him a Nobel Prize for explaining a drug your great-grandparents already trusted with their lives. That pattern runs through the whole pharmacy. Lithium has been the gold standard for bipolar disorder since 1949, and researchers are still fighting about what it does in the brain. General anesthesia puts 300 million people…